Re: [PATCH v3] tpm: Enable hwrng only for Pluton on AMD CPUs

[Jarkko Sakkinen]

On Mon Sep 4, 2023 at 9:00 PM EEST, Jarkko Sakkinen wrote:
> On Mon Aug 28, 2023 at 3:35 AM EEST, Mario Limonciello wrote:
> > On 8/27/2023 13:12, Jarkko Sakkinen wrote:
> > > On Wed Aug 23, 2023 at 9:58 PM EEST, Mario Limonciello wrote:
> > >> On 8/23/2023 12:40, Jarkko Sakkinen wrote:
> > >>> On Wed Aug 23, 2023 at 11:23 AM EEST, Paul Menzel wrote:
> > >>>> Dear Jarkko,
> > >>>>
> > >>>>
> > >>>> Thank you for your patch.
> > >>>>
> > >>>>
> > >>>> Am 23.08.23 um 01:15 schrieb Jarkko Sakkinen:
> > >>>>> The vendor check introduced by commit 554b841d4703 ("tpm: Disable RNG for
> > >>>>> all AMD fTPMs") doesn't work properly on a number of Intel fTPMs.  On the
> > >>>>> reported systems the TPM doesn't reply at bootup and returns back the
> > >>>>> command code. This makes the TPM fail probe.
> > >>>>>
> > >>>>> Since only Microsoft Pluton is the only known combination of AMD CPU and
> > >>>>> fTPM from other vendor, disable hwrng otherwise. In order to make sysadmin
> > >>>>> aware of this, print also info message to the klog.
> > >>>>>
> > >>>>> Cc: stable@xxxxxxxxxxxxxxx
> > >>>>> Fixes: 554b841d4703 ("tpm: Disable RNG for all AMD fTPMs")
> > >>>>> Reported-by: Todd Brandt <todd.e.brandt@xxxxxxxxx>
> > >>>>> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217804
> > >>>>> Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
> > >>>>
> > >>>> Mario’s patch also had the three reporters below listed:
> > >>>>
> > >>>> Reported-by: Patrick Steinhardt <ps@xxxxxx>
> > >>>> Reported-by: Ronan Pigott <ronan@xxxxxx>
> > >>>> Reported-by: Raymond Jay Golo <rjgolo@xxxxxxxxx>
> > >>>
> > >>> The problem here is that checkpatch throws three warnings:
> > >>>
> > >>> WARNING: Reported-by: should be immediately followed by Closes: with a URL to the report
> > >>> #19:
> > >>> Reported-by: Patrick Steinhardt <ps@xxxxxx>
> > >>> Reported-by: Ronan Pigott <ronan@xxxxxx>
> > >>>
> > >>> WARNING: Reported-by: should be immediately followed by Closes: with a URL to the report
> > >>> #20:
> > >>> Reported-by: Ronan Pigott <ronan@xxxxxx>
> > >>> Reported-by: Raymond Jay Golo <rjgolo@xxxxxxxxx>
> > >>>
> > >>> WARNING: Reported-by: should be immediately followed by Closes: with a URL to the report
> > >>> #21:
> > >>> Reported-by: Raymond Jay Golo <rjgolo@xxxxxxxxx>
> > >>> Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
> > >>>
> > >>
> > >> FWIW I observed the same checkpatch warning when I submitted my version
> > >> of the patch.  I figured it's better to ignore the warning and attribute
> > >> everyone who reported the issue affected them.
> > > 
> > > OK so:
> > > 
> > > 1. checkpatch.pl is part of the kernel process.
> > > 2. Bugzilla is not part of the kernel process.
> > > 
> > > Why emphasis on 1?
> > > 
> > > BR, Jarkko
> >
> > The reason I submitted it this way is because of this quote from the 
> > documentation [1].
> >
> > "Check your patches with the patch style checker prior to submission 
> > (scripts/checkpatch.pl). Note, though, that the style checker should be 
> > viewed as a guide, not as a replacement for human judgment. If your code 
> > looks better with a violation then its probably best left alone."
> >
> > I wanted the patch to capture and attribute all those that reported it 
> > not just the "first one".  Like I said previously, it's better to have a 
> > collection of people to ping to notify if something needs to be reverted.
> >
> > [1] 
> > https://www.kernel.org/doc/html/latest/process/submitting-patches.html#style-check-your-changes
>
> Please denote also that kernel bugzilla is not mentioned in the page
> that you put as a reference, and only reporter in the LKML has been
> Todd.

Also the bugzilla is ambiguous because in this thread I get a picture
that any possible commenter is a reporter, and at the same time bugzilla
has a *specific field* for a reporter.

How do the comments and the field for the reporter relate, and how they
should be interpreted?

BR, Jarkko